Cancelled Drug Tests

A cancelled DOT Drug Test is not a positive or negative result.  The next step depends on the reason for cancellation.

Collector Errors

Random Testing

• The Random Selection is marked complete.  No Re-Test is required.

Pre-Employment Testing

• A new Pre-Employment DOT Drug Test is required before the Driver can be added to the Random Pool.

Examples of Collector Errors include:

• Collector Signature was missing and could not be corrected
• Wrong Custody and Control Form (CCF) was used
• Required CCF copy was not provided
• Specimen ID Number did not match the CCF
• Specimen ID Numbers on the bottles and CCF did not match
• Insufficient Quantity of Specimen was submitted for testing
• Bottle A contained an insufficient amount of specimen
• An Uncorrected Flaw or Fatal Flaw caused the test to be rejected

Cancelled Tests Requiring Direct Observation

DOT requires Drivers to Get Tested Immediately under Direct Observation when Notified.  Failure to Get Tested Immediately is a Refusal-to-Test.

Invalid Result – Abnormal pH

• Urine pH in a DOT Drug Test should be between 4.5–8. Levels outside this range may indicate Tampering, Dilution, or Substitution and may require an Immediate Recollection under Direct Observation.

Invalid Result – Immunoassay Interference

• Certain Medications, Metabolites, or abnormal specimen characteristics may interfere with laboratory testing and cause an Invalid Result.  An Immediate Recollection under Direct Observation may be required.

Invalid Result – Invalid Creatinine

• Creatinine helps determine whether a urine specimen is valid.  Very low or abnormal Creatinine Levels may indicate Dilution or Substitution and may require an Immediate Recollection under Direct Observation.

Invalid Result – Bottle A & Bottle B – Different Appearance

• DOT Drug Tests are divided into Bottle A (Primary Specimen) and Bottle B (Split Specimen). If the bottles have a different appearance, it may indicate Tampering or Contamination and may require an Immediate Recollection under Direct Observation.

Invalid Result – Temperature Out-of-Range

• Urine temperature must be between 90°F–100°F at the time of collection.  A Temperature Out-of-Range may indicate Tampering or Substitution and requires a second collection under Direct Observation.

Invalid Result – Specific Gravity

• Specific Gravity measures the concentration of a urine specimen.  Abnormal levels may indicate Dilution or Substitution and may require an Immediate Recollection under Direct Observation.

Observed Drug Tests

Order DOT Drug Tests online through your Express Labs Account or use the Quest Paper Forms we provide.  Once enrolled, only DOT Drug Tests ordered through Express Labs or completed using Express Labs Quest Paper Forms are accepted.

• Select Return-to-Duty or Follow-Up as the Reason for Testing.  Pre-Employment & Random Tests are not Observed.
• Call the Collection Site to confirm a Same-Gender Collector is available for Direct Observation and they are accepting walk-ins
• Complete Drug Testing Instructions

Express Labs FMCSA Random Drug & Alcohol Consortium
Cancelled Drug Tests | Updated 2026